Magnetic Nanoparticle-Doped Ordered Mesoporous Carbon Fibers from Scalable Wet Spinning for Broadband Microwave Absorption

Integrating ordered mesoporous architectures and functional nanoparticles into carbon fibers holds great promise for various advanced applications. However, current methods are primarily based on electrospun mesoporous carbon nanofibers, which suffer from high cost, low throughput, and poor scalability. The fabrication of macroscale ordered mesoporous carbon fibers (OMCFs) doped with functional nanoparticles using cost-effective and industrially viable methods, such as wet spinning, remains a significant challenge. Herein, we report a scalable wet-spinning strategy to fabricate macroscale Fe 7 S 8 nanoparticle-doped ordered mesoporous carbon fibers (Fe 7 S 8 @OMCFs) using the commodity thermoplastic elastomer of polystyrene- block -poly(ethylene- ran -butylene)- block -polystyrene triblock copolymer (SEBS) as a versatile carbon precursor. Sulfonation and cross-linking of SEBS enable uniform Fe 3+ incorporation and subsequent formation of Fe 7 S 8 nanoparticles during carbonization while preserving the ordered mesoporous architecture throughout the entire fiber. The resulting Fe 7 S 8 @OMCFs exhibit a high specific surface area (387 m 2 /g), well-defined mesoporosity, and homogeneously dispersed magnetic nanoparticles, resulting in exceptional microwave absorption performance due to superior impedance matching and enhanced electromagnetic loss. These fibers achieve a minimum reflection loss of −35.7 dB and a broadband effective absorption bandwidth of 6.3 GHz at a low thickness of 1.6 mm. CST simulations further demonstrate significant radar cross-sectional reduction across multiple incident angles. This work overcomes longstanding fabrication limitations and offers a scalable, generalizable route to macroscale OMCFs for multifunctional applications.